Wireless local area network antenna array

ABSTRACT

A wireless local area network (“WLAN”) antenna array (“WLANAA”) is disclosed. The WLANAA may include a circular housing having a plurality of radial sectors and a plurality of primary antenna elements. Each individual primary antenna element of the plurality of primary antenna elements may be positioned within an individual radial sector of the plurality of radial sectors.

PRIORITY CLAIM AND CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the following:

-   -   1. U.S. patent application Ser. No. 13/477,785, titled “Wireless        local Area Network Antenna Array,” by Abraham Hartenstein, filed        on May 22, 2012;    -   2. U.S. patent application Ser. No. 11/816,064, titled “Antenna        Architecture of a Wireless LAN Array,” by Abraham Hartenstein,        filed on Apr. 3, 2008;    -   3. PCT patent application no. PCT/US2006/008747, titled “Antenna        Architecture of a Wireless LAN Array,” and    -   4. Prov. App. Ser. No. 60/660,393, titled “Antenna Architecture        of a Wireless LAN Array,” by Abraham Hartenstein, filed on Mar.        9, 2005;        the contents of which are incorporated by reference herein.

The following provisional applications, non-provisional applications,and PCT applications are incorporated by reference herein:

-   -   1. Prov. App. Ser. No. 60/660,171, titled “Wireless LAN Array,”        by Dirk I. Gates, Ian Laity, Mick Conley, Mike de la Garrigue,        and Steve Smith, filed on Mar. 9, 2005;    -   2. Prov. App. Ser. No. 60/660,276, titled “Wireless LAN Array,”        by Dirk I. Gates, Ian Laity, Mick Conley, Mike de la Garrigue,        and Steve Smith, filed on Mar. 9, 2005;    -   3. Prov. App. Ser. No. 60/660,375, titled “Wireless Access        Point,” by Dirk I. Gates and Ian Laity, filed on Mar. 9, 2005;    -   4. Prov. App. Ser. No. 60/660,275, titled “Multi-Sector Access        Point Array,” by Dirk I. Gates Ian Laity, Mick Conley, Mike de        la Garrigue, and Steve Smith, filed on Mar. 9, 2005;    -   5. Prov. App. Ser. No. 60/660,210, titled “Media Access        Controller For Use In A Multi-Sector Access Point Array,” by        Mike de la Garrigue and Drew Bertagna filed on Mar. 9, 2005;    -   6. Prov. App. Ser. No. 60/660,174, titled “Queue Management        Controller For Use In A Multi-Sector Access Point Array,” by        Mike de la Garrigue and Drew Bertagna filed on Mar. 9, 2005;    -   7. Prov. App. Ser. No. 60/660,394, titled “Wireless LAN Array,”        by Dirk I. Gates, Ian Laity, Mick Conley, Mike de la Garrigue,        and Steve Smith, filed on Mar. 9, 2005;    -   8. Prov. App. Ser. No. 60/660,209, titled “Wireless LAN Array        Architecture,” by Dirk I. Gates, Ian Laity, Mick Conley, Mike de        la Garrigue, and Steve Smith, filed on Mar. 9, 2005;    -   9. Prov. App. Ser. No. 60/660,269, titled “Load Balancing In A        Multi-Radio Wireless Lan Array Based On Aggregate Mean Levels,”        by Mick Conley filed on Mar. 9, 2005;    -   10. Prov. App. Ser. No. 60/660,392, titled “Advanced Adjacent        Channel Sector Management For 802.11 Traffic,” by Mick Conley        filed on Mar. 9, 2005;    -   11. Prov. App. Ser. No. 60/660,391, titled “Load Balancing In A        Multi-Radio Wireless Lan Array Based On Aggregate Mean Levels,”        by Shaun Clem filed on Mar. 9, 2005;    -   12. Prov. App. Ser. No. 60/660,277, titled “System for        Transmitting and Receiving Frames in a Multi-Radio Wireless LAN        Array,” by Dirk I. Gates and Mike de la Garrigue, filed on Mar.        9, 2005;    -   13. Prov. App. Ser. No. 60/660,302, titled “System for        Allocating Channels in a Multi-Radio Wireless LAN Array,” by        Dirk I. Gates and Kirk Mathews, filed on Mar. 9, 2005;    -   14. Prov. App. Ser. No. 60/660,376, titled “System for        Allocating Channels in a Multi-Radio Wireless LAN Array,” by        Dirk I. Gates and Kirk Mathews, filed on Mar. 9, 2005;    -   15. Prov. App. Ser. No. 60/660,541, titled “Media Access        Controller For Use In A Multi-Sector Access Point Array,” by        Dirk I. Gates and Mike de la Garrigue, filed on Mar. 9, 2005;    -   16. PCT patent application no. PCT/US2006/008743, titled        “Wireless LAN Array,” filed on Mar. 9, 2006;    -   17. PCT patent application no. PCT/US2006/008696, titled        “Assembly and Mounting for Multi-Sector Access Point Array,”        filed on Mar. 9, 2006;    -   18. PCT patent application no. PCT/US2006/08698, titled “System        for Allocating Channels in a Multi-Radio Wireless LAN Array,”        filed Mar. 9, 2006; and    -   19. PCT patent application no. PCT/US2006/008744, titled “Media        Access Controller for use in a Multi-Sector Access Point Array,”        filed on Mar. 9, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to communication devices, and moreparticularly to antennas for media access controllers.

2. Related Art

The use of wireless communication devices for data networking is growingat a rapid pace. Data networks that use “WiFi” (“Wireless Fidelity”),also known as “Wi-Fi,” are relatively easy to install, convenient touse, and supported by the IEEE 802.11 standard. WiFi data networks alsoprovide performance that makes WiFi a suitable alternative to a wireddata network for many business and home users.

WiFi networks operate by employing wireless access points that provideusers, having wireless (or “client”) devices in proximity to the accesspoint, with access to varying types of data networks such as, forexample, an Ethernet network or the Internet. The wireless access pointsinclude a radio that operates according to one of three standardsspecified in different sections of the IEEE 802.11 specification.Generally, radios in the access points communicate with client devicesby utilizing omni-directional antennas that allow the radios tocommunicate with client devices in any direction. The access points arethen connected (by hardwired connections) to a data network system thatcompletes the access of the client device to the data network.

The three standards that define the radio configurations are:

-   1. IEEE 802.11a, which operates on the 5 GHz frequency band with    data rates of up to 54 Mbs;-   2. IEEE 802.11b, which operates on the 2.4 GHz frequency band with    data rates of up to 11 Mbs; and-   3. IEEE 802.11g, which operates on the 2.4 GHz frequency band with    data rates of up to 54 Mbs.

The 802.11b and 802.11g standards provide for some degree ofinteroperability. Devices that conform to 802.11b may communicate with802.11g access points. This interoperability comes at a cost as accesspoints will switch to the lower data rate of 802.11b if any 802.11bdevices are connected. Devices that conform to 802.11a may notcommunicate with either 802.11b or 802.11g access points. In addition,while the 802.11a standard provides for higher overall performance,802.11a access points have a more limited range of approximately 60 feetcompared with the approximate 300 feet range offered by 802.11b or802.11g access points.

Each standard defines ‘channels’ that wireless devices, or clients, usewhen communicating with an access point. The 802.11b and 802.11gstandards each allow for 14 channels. The 802.11a standard allows for 23channels. The 14 channels provided by 802.11b and 802.11g include only 3channels that are not overlapping. The 12 channels provided by 802.11aare non-overlapping channels.

Access points provide service to a limited number of users. Accesspoints are assigned a channel on which to communicate. Each channelallows a recommended maximum of 64 clients to communicate with theaccess point. In addition, access points must be spaced apartstrategically to reduce the chance of interference, either betweenaccess points tuned to the same channel, or to overlapping channels. Inaddition, channels are shared. Only one user may occupy the channel atany give time. As users are added to a channel, each user must waitlonger for access to the channel thereby degrading throughput.

Another degradation of throughput as the number of clients grows is theresult of the use of omni-directional antennas. Unfortunately, currentaccess point technology employs typically one or two radios in closeproximity that results in interference, which reduces throughput. In anexample of a two radio access point, both radios may be utilized asaccess points (i.e., each radio communicates with a different clientdevice) or one radio may function as the access point while the otherradio functions as a backhaul, i.e., a communication channel from theaccess point to a network backbone, central site, and/or other accesspoint. Typically, the interference resulting from the different antennasutilized with these radios limits the total throughput available and, asa result, reduces traffic efficiency at the access point.

Unfortunately, in the existing WiFi technologies, there is a need todeploy mesh like networks of access points to increase the coverage areaof a WiFi communication system. As the number of access points increasesso does the complexity of implementing the communication system.Therefore, there is a need for a radio and antenna architecture capableof operating in a mesh like networks of access points without causingradio interference that reduces the throughput of the network.

SUMMARY

A wireless local area network (“WLAN”) antenna array (“WLANAA”) isdisclosed. The WLANAA may include a circular housing having a pluralityof radial sectors and a plurality of primary antenna elements. Eachindividual primary antenna element of the plurality of primary antennaelements may be positioned within an individual radial sector of theplurality of radial sectors.

The WLANAA may further include a plurality of main reflector elementswherein each main reflector element of the plurality of main reflectorelements is located adjacent to each antenna element and a plurality ofabsorber elements, wherein each absorber element of the plurality of theabsorber elements is located between an adjacent pair of primary antennaelements. The WLANAA may also include a plurality of deflector elementswherein each deflector element of the plurality of deflector elements islocated adjacent to each primary antenna element.

Other systems, methods and features of the invention will be or willbecome apparent to one with skill in the art upon examination of thefollowing figures and detailed description. It is intended that all suchadditional systems, methods, features and advantages be included withinthis description, be within the scope of the invention, and be protectedby the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingfigures. The components in the figures are not necessarily to scale,emphasis instead being placed upon illustrating the principles of theinvention. In the figures, like reference numerals designatecorresponding parts throughout the different views.

FIG. 1 is a top view of an example of an implementation of a WirelessLocal Area Network (“WLAN”) Antenna Array (“WLANAA”).

FIG. 2 is a top view of an example of another implementation of a WLANAAutilizing twelve (12) radial sectors.

FIG. 3 is a side view of an example of an implementation of anindividual primary antenna element within a radial sector shown in FIG.2.

FIG. 4 is an etched circuit diagram of an example of an implementationof the individual primary antenna element shown in FIGS. 1, 2, and 3.

FIG. 5 is a plot of an example of an azimuth radiation pattern of theindividual primary antenna element shown in FIG. 4.

FIG. 6 is a plot of an example of an azimuth radiation pattern of theindividual primary antenna element with absorber elements shown in FIG.4.

FIG. 7 is a plot of an example of an elevation radiation pattern of theindividual primary antenna element in FIG. 4.

FIG. 8 is a plot of an example of plurality of azimuth radiationpatterns of the plurality of primary antenna elements with absorberelements shown in FIG. 2.

FIG. 9A is an etched circuit diagram of an example of an implementationof an individual secondary antenna element.

FIG. 9B is an etched circuit diagram of an example of an implementationof two secondary antenna elements.

FIG. 9C is a side view of an example of an implementation of anindividual secondary antenna element within a radial sector shown inFIG. 2.

FIG. 10 is a plot of an example of a plurality of azimuth radiationpatterns of the plurality of secondary antenna elements.

FIG. 11 is a plot of an example of an azimuth radiation pattern of anindividual secondary antenna element in a listening mode.

FIG. 12A is front view of an etched circuit diagram of an example of animplementation of the individual primary antenna element shown in FIGS.1, 2, and 3.

FIG. 12B is rear view of an etched circuit diagram of an example of animplementation of the individual primary antenna element shown in FIGS.1, 2, and 3 and an individual secondary antenna element shown in FIG. 9.

FIG. 13 is an etched circuit diagram of an example of anotherimplementation of the individual primary antenna element and twosecondary antenna elements in an array form.

FIG. 14 is an etched circuit diagram of an example of anotherimplementation of the individual primary antenna element shown in FIGS.1, 2, and 3.

FIG. 15 is prospective view of an example of another implementation of aWLANAA utilizing eight (8) radial sectors.

FIG. 16 is a top-view and side-view of the WLANAA.

FIG. 17 is a cut-view of an example of an implementation of anindividual primary antenna element shown in FIGS. 1, 2, and 3 in anindividual radial sector.

FIG. 18 is a flowchart showing an example of an implementation ofprocess performed by the WLANAA.

DETAILED DESCRIPTION

In the following description of the preferred embodiment, reference ismade to the accompanying drawings that form a part hereof, and whichshow, by way of illustration, a specific embodiment in which theinvention may be practiced. Other embodiments may be utilized andstructural changes may be made without departing from the scope of thepresent invention.

A wireless local area network (“WLAN”) antenna array (“WLANAA”) isdisclosed. The WLANAA may include a circular housing having a pluralityof radial sectors and a plurality of primary antenna elements. Eachindividual primary antenna element of the plurality of primary antennaelements may be positioned within an individual radial sector of theplurality of radial sectors.

In general, the WLANAA is a multi-sector antenna system that has highgain (about 6 dBi) and radiates a plurality of radiation patterns that“carve” up the airspace into equal sections of space or sectors with acertain amount of pattern overlap to assure continuous coverage for aclient device in communication with the WLANAA. The radiation patternoverlap may also assistant in managing a plurality of client devicessuch that adjacent sectors may assist each other in managing the numberof client devices served with the highest throughput as controlled by anarray controller. The WLANAA provides increased directional transmissionand reception gain that allow the WLANAA and its respective clientdevices to communicate at greater distances than standardomni-directional antenna systems, thus producing an extended coveragearea when compared to an omni-directional antenna system.

The WLANAA is capable of creating a coverage pattern that resembles atypical omni-directional antenna system but covers approximately fourtimes the area and twice the range. In general, each radio frequency(“RF”) sector is assigned a non-overlapping channel by an ArrayController.

In FIG. 1, a top view of an example of an implementation of a WLANAA 100is shown. The WLANAA 100 may have a circular housing 102 having aplurality of radial sectors. As an example, there may be sixteen (16)radial sectors 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124,126, 128, 130, 132, and 134 within the circular housing 102. The WLANAA100 may also include a plurality of primary antenna elements (such as,for example, sixteen (16) primary antenna elements 136, 138, 140, 142,144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, and 166). Eachindividual primary antenna element of the plurality of primary antennaelements may be positioned within an individual radial sector of theplurality of radial sectors such as, for example, primary antennaelements 136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158,160, 162, 164, and 166 may be positioned within corresponding radialsectors 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128,130, 132, and 134, respectively. Additionally, each radial sector 104,106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132,and 134 may include absorber elements 168, 170, 172, 174, 176, 178, 180,182, 184, 186, 188, 190, 192, 194, 196, and 198, respectively, that maybe positioned between adjacent primary antenna elements 136, 138, 140,142, 144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, and 166. Inorder to reduce mutual coupling and any potential sidelobes above acertain level resulting from the array factoring of the primary antennaelements 136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158,160, 162, 164, and 166, adjacent primary antenna elements are spacedmore than a wavelength apart from each other. The absorber elements 168,170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 194, 196,and 198, may be any material capable of absorbing electromagnetic energysuch as, for example, foam-filled graphite-isolated insulators, ferriteelements, dielectric elements, or other similar types of materials.

Each of the primary antenna elements 136, 138, 140, 142, 144, 146, 148,150, 152, 154, 156, 158, 160, 162, 164, and 166 may be a two elementbroadside array element such as coupled line dipole antenna element. Itis appreciated by those skilled in the art that other types of arrayelements may also be utilizing including but not limited to a patch,monopole, notch, Yagi-Uda type antenna elements.

Similarly in FIG. 2, a top view of an example of another implementationof a WLANAA 200 utilizing twelve (12) radial sectors is shown. TheWLANAA 200 may have a circular housing 202 having a plurality of radialsectors 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, and 226.The WLANAA 200 may also include twelve (12) primary antenna elements228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, and 250. Eachindividual primary antenna element of the plurality of primary antennaelements may be positioned within an individual radial sector of theplurality of radial sectors such as, for example, primary antennaelements 228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, and 250may be positioned within corresponding radial sectors 204, 206, 208,210, 212, 214, 216, 218, 220, 222, 224, and 226, respectively.Additionally, each radial sector 204, 206, 208, 210, 212, 214, 216, 218,220, 222, 224, and 226 may include absorber elements 252, 254, 256, 258,260, 262, 264, 266, 268, 270, 272, and 274, respectively, that may bepositioned between adjacent primary antenna elements 228, 230, 232, 234,236, 238, 240, 242, 244, 246, 248, and 250. In order to reduce mutualcoupling and any potential sidelobes above a certain level resultingfrom the array factoring of the primary antenna elements 228, 230, 232,234, 236, 238, 240, 242, 244, 246, 248, and 250, adjacent primaryantenna elements are spaced more than a wavelength apart from eachother. As an example, adjacent primary antenna elements may be spacedtwo or more wavelengths away from each other. Again, the absorberelements 252, 254, 256, 258, 260, 262, 264, 266, 268, 270, 272, and 274,may be any material capable of absorbing electromagnetic energy such as,for example, foam-filled graphite-isolated insulators, ferrite elements,dielectric elements, or other similar types of materials.

While in FIG. 2 only one individual primary antenna is shown per radialsector, there may also be a plurality of secondary antenna elementspresent where each individual secondary antenna element may be locatedin the same radial sector as a primary antenna element.

In FIG. 3, a side view of an example of an implementation of anindividual primary antenna element 300 within a single radial sector 302is shown. The single radial sector 302 may include a main reflector 304and deflector 306 that may be in signal communication via signal path308. Both the main reflector 304 and deflector 306 may be constructedfrom numerous types of conductive material such as, for example, copper,aluminum, gold, nickel, tin, brass, iron, steel, or other types ofconductive metal alloys or ceramic-metallic materials, or a combinationof these materials.

The primary antenna element 300 may be positioned a reflector distance308 away from the main reflector 304. The reflector distance 308 may beequal to approximately a quarter wavelength of the frequency ofoperation of the primary antenna element 300. Similarly, the primaryantenna element 300 may be positioned a deflector distance 310 away fromthe deflector 306. The deflector distance 310 may be equal toapproximately a half wavelength of the frequency of operation of theprimary antenna element 300. As an example, the primary antenna elementmay be an IEEE 802.11a antenna element that covers the 5 GHz frequencyband and may be implemented as a coupled line dipole antenna arrayhaving two or more coupled line dipole elements. As an example for802.11a, the primary reflector distance 308 may be approximately 0.450inches (i.e., about a quarter wavelength) and the primary deflectordistance 312 may be approximately 0.860 inches (i.e., about a halfwavelength).

Both main reflector 304 and deflector 306 may act as ground planesrelative to the primary antenna element 300. The main reflector 304 anddeflector 306 focus the energy outwards and below the horizon that is anoptimum for near-field and far-field coverage as shown in FIG. 7.

In an example of operation, the main reflector 304 acts as a finiteground plane relative to the primary antenna element 300 to produce areflector antenna. It is appreciated by those skilled in the art thatthe reflector antenna produces a radiation pattern that may bedetermined by utilizing both antenna image theory and the geometrictheory of diffraction (“GTD”). Generally, the reflector distance 308determines the image distance 312 of image 314 of the primary antennaelement 300 on the other side of the main reflector 304. From antennaimage theory the pattern of the reflector antenna would be equal toE_(θ)(θ)=E(θ)sin(βd cos(θ)) plus GTD effects, where E is the electricfield radiation pattern in the θ plane (i.e., azimuth or H-plane), β isthe phase constant for a plane wave, and d is the reflector distance308.

According to GTD, the radiation fields produced by the reflector antennamay be divided into three regions (not shown). In the first region infront of the main reflector 304, the radiated field is given by theresultant of the field coming directly from the primary antenna element300 (the direct field) and the field reflected off the main reflector304 (the reflected field). In the second region to the sides of the mainreflector 304, there is only the direct field from the dipole (i.e.,there is no reflection from the main reflector 304) because the secondregion is in the shadow of the reflected wave but not the direct wave soit may be known as the region of “partial shadow.” In the third regionbehind the main reflector 304, the main reflector 304 acts as anobstacle producing a full shadow with no direct or reflected fields.

In FIG. 4, an etched circuit diagram of an example of an implementationof the individual primary antenna element 400 is shown. As an example,the primary antenna element 400 may be a patch antenna array that may beetched on a substrate or printed on a printed circuit board (“PCB”). Theprimary antenna element 400 may be a coupled line dipole antenna arrayhaving two coupled line dipole elements 402 and 404. The two coupledline dipole elements 402 and 404 may be spaced 406 approximatelyhalf-a-wavelength apart so as to minimize any azimuth sidelobesresulting from the array factor and so as to minimize the couplingbetween the radial sectors.

A feed network 408 is coupled to the coupled line dipole elements 402and 404. The feed network 408 is a coupled line that helps in minimizingany parasitic radiation from the feed lines 410. The feed network 408includes a hybrid-T junction (generally known as a “magic-T”) Baluntransformer to convert from unbalanced to balanced mode. The magic-T isa three-port device that converts the coupled line feedlines into asingle ended microstrip feedline and as a result converts the singleended input (i.e., the microstrip line) into a balanced line with thatallows impedance transportation. As an example, the primary antennaelement 400 may have a gain value of 6 dB.

In an example of operation as an 802.11a antenna array, the primaryantenna element 400 has a spacing between coupled line dipole elements402 and 404 that is spaced 406 approximately half-a-wavelength apart soas to minimize any azimuth sidelobes resulting from the array factor.This produces sidelobes that are generally lower than about 16 dB fromthe peak of the main beam of the radiation pattern of the primaryantenna element 400 as shown in FIG. 5.

In FIG. 5, a plot 500 of an example of an azimuth radiation pattern 502in the azimuth plane 503 of the individual primary antenna element ofFIG. 4 is shown. In this example, the individual primary antenna elementis a coupled line dipole antenna array 400 and the spacing between thetwo coupled line dipole elements 402 and 404 may be spaced 406approximately half-a-wavelength apart. This produces first sidelobes 504and 506 that have sidelobe peak values 508 and 510 that are generallylower than about 16 dB from the peak 512 of the main beam 514 of theradiation pattern of the primary antenna element 400.

In an example of operation as an 802.11a antenna array, the primaryantenna element spacing between adjacent elements shown in FIGS. 1 and 2may allow isolation of certain values between primary antenna elementsbecause of the spacing effect between adjacent elements being multiplewavelength in length. This isolation combined with the array factorisolation for the sidelobes created by the primary antenna elementcombine for a combined isolation of about 40 dB minimum that representsthe radial sector isolation between adjacent radial sectors. Theabsorber elements shown in FIGS. 1 and 2 enhance this radial sectorisolation even further for a combined radial sector isolation of about55 to 65 dB as FIG. 6.

In FIG. 6, a plot 600 of an example of an azimuth radiation pattern 602in the azimuth plane 604 of the individual primary antenna element withthe absorber elements of FIGS. 2 and 4 is shown. Similar to FIG. 5, inthis example the individual primary antenna element is a coupled linedipole antenna array 400 and the spacing between the two coupled linedipole elements 402 and 404 may be spaced 406 approximatelyhalf-a-wavelength apart with absorber elements on both sides of theprimary antenna element. This produces first sidelobes 606 and 608 thathave sidelobe peak values 610 and 612 that are generally lower thanabout 24 dB from the peak 614 of the main beam 616 of the radiationpattern 602 of the primary antenna element 400.

In FIG. 7, a plot 700 of an example of an elevation radiation pattern702 in the elevation plane 704 of the individual primary antenna elementof FIGS. 2 and 4 is shown. In an example of operation, the mainreflector and the deflector causes the main beam 704 in the elevationpattern 702 to become more directive pointed downward 706 approximately5 to 10 degrees from the horizontal plane 708. The main reflector helpsminimize the backlobe 710 of the antenna.

As described above, in operation the combined radial sector isolationbetween adjacent radial sectors is about 55 to 65 dB. This combinedradial sector isolation increase gradually between non-adjacent radialsectors that are spaced farther apart. Additional improvements toisolation are possible by utilizing different channels on the radios ofadjacent radial sectors known as non-overlapping channel isolation. Thenon-overlapping channel isolation may add another 10 dB or more ofisolation for a total isolation between adjacent radial sectors of 75 dBor more.

In FIG. 8, a plot 800 of an example of plurality of azimuth radiationpatterns 802, 804, 806, 808, 810, 812, 814, 816, 818, 820, 822, and 824in the azimuth plane 825 of the plurality of primary antenna elementswithin an antenna array 826 with absorber elements of FIG. 2 is shown.In this example, the primary antenna elements may be 802.11a antennaelements. The plurality of azimuth radiation patterns 802, 804, 806,808, 810, 812, 814, 816, 818, 820, 822, and 824 may provide coverage foran example floor plan 828 of an office space. The radiation patterns802, 804, 806, 808, 810, 812, 814, 816, 818, 820, 822, and 824 mayoverlap with adjacent radiation pattern at pattern overlaps 830, 832,834, 836, 838, 840, 842, 844, 846, 848, 850, and 852. The radiationpatterns may overlap to allow client devices (not shown) to move betweenareas covered by adjacent radial sectors without losing communication.

In FIG. 9A, an etched circuit diagram of an example of an implementationof an individual secondary antenna element is shown. As an example, thesecondary antenna element may be an IEEE 802.11b or 802.11g antennaelement that covers the 2,400 to 2,483 MHz range and may be implementedas a bent monopole antenna 900 or a two element array of bent monopolesantenna elements 902 and 904 as shown in FIG. 9B. The secondary antennaelement may be either etched on a substrate or printed on a PCB.

As shown in FIG. 9C, the secondary antenna element 906 may be positioneda secondary reflector distance 908 from the main reflector 910 and asecondary deflector distance 912 from the deflector 914. Similar to FIG.3, the main reflector 910 and deflector 914 may be in signalcommunication via signal path 916. As an example for 802.11b or 802.11g,the secondary reflector distance 908 may be approximately 0.450 inchesand the secondary deflector distance 912 may be 1.30 inches. Utilizingthese values secondary antenna element may have a gain value of 2 dB inFIG. 9A and 4 dB in FIG. 9B. Additionally, the coverage varies betweenthe secondary antenna elements shown in FIGS. 9A and 9B. In FIG. 9A, thesingle bent monopole 900 may have, as an example, a 3 dB azimuthbeamwidth of approximately 90 degrees while the dual bent monopole 902and 904 antenna array of FIG. 9B may have a 3 dB azimuth beamwidth ofapproximately 50 degrees.

Similar to FIG. 3, both main reflector 910 and deflector 914 may act asground planes relative to the secondary antenna element 906. The mainreflector 910 and deflector 912 focus the energy outwards and below thehorizon that is an optimum for near-field and far-field coverage. Ingeneral, the secondary antenna element 906 is not influenced by theabsorber elements (not shown) because the absorber elements have athickness that has been optimized to attenuate radiation from theprimary antenna elements.

In FIG. 10, a plot 1000 of an example of plurality of azimuth radiationpatterns 1002, 1004, and 1006 in the azimuth plane 1008 of the pluralityof secondary antenna elements within an antenna array 1010 is shown. Inthis example, the secondary antenna elements may be 802.11b or 802.11gantenna elements. The plurality of azimuth radiation patterns 1002,1004, and 1006 may provide coverage for an example floor plan 1012 of anoffice space. The radiation patterns 1002, 1004, and 1006 may overlapwith adjacent radiation patterns at pattern overlaps 1014, 1016, and1018. The radiation patterns may overlap to allow client devices (notshown) to move between areas covered by adjacent radial sectors withoutlosing communication.

In FIG. 11, a plot 1100 of an example of an azimuth radiation pattern1102 in the azimuth plane 1104 of an individual secondary antennaelement 1106 in a listening mode is shown. In this example, thesecondary antenna element 1106 may be an 802.11b or 802.11g antennaelement. The azimuth radiation pattern 1102 may be an omni-directionradiation pattern that provides coverage for an example floor plan 1108of an office space.

In FIG. 12A, a front view of an etched circuit diagram of an example ofan implementation of the individual primary antenna element of FIGS. 1,2, and 3 is shown. In FIG. 12B, a rear view of an etched circuit diagramof an example of an implementation of the individual primary antennaelement of FIGS. 1, 2, and 3 and an individual secondary antenna elementof FIG. 9 is shown.

Similar to FIG. 4, in this example the primary antenna element may be apatch antenna array that may be etched on a one layer substrate orprinted on a layer of a PCB. The primary antenna element may be coupledline dipole antenna array having two coupled line dipole elements. Thetwo coupled line dipole elements may be spaced 1200 approximatelyhalf-a-wavelength apart so as to minimize any azimuth sidelobesresulting from the array factor and so as to minimize the couplingbetween the radial sectors.

In FIGS. 12A and 12B, the coupled line dipole is shown in two parts thatinclude a backplane part 1202 and a front-plane part 1204. The backplanepart 1202 may be etched on a back layer of a substrate or printed on thebackside of a PCB while the front-plane part 1204 may be a microstripfed dipole that is etched on a front layer of the substrate or printedon the front-plane of the PCB along with a magic-T feed network 1206.When combined, the backplane part 1202 and front-plane part 1204 act asa complete coupled line dipole as previously described in FIG. 4.

In FIG. 12B, a secondary antenna element 1208 is also shown. Thesecondary antenna element 1208 may be a single bent monopole antenna asdescribed in FIGS. 9A, 9B, and 9C or a two bent monopole array as shownin FIG. 13. In an example of operation, if the primary antenna elementis an 802.11a antenna element and the secondary antenna element is an802.11b or 802.11g antenna element, the primary antenna element does notinterfere with the secondary antenna element and vise-versa.

In FIG. 13, an etched circuit diagram of an example of anotherimplementation of the individual primary antenna element 1300 and twosecondary antenna elements 1302 and 1304 in a single radial sector 1306is shown. By adding another bent monopole antenna 1304 in the radialsector 1306 that is arrayed with the first bent monopole antenna 1302the 802.11b or 802.11g antenna directivity may be increase from 2 dBi(for a single bent monopole) to about 4 dBi. This configuration does notinterfere with the 802.11a antenna 1300.

In FIG. 14, an etched circuit diagram of an example of anotherimplementation of the individual primary antenna element 1400 of FIGS.1, 2, and 3 is shown. Instead of a two dipole array, as shown in FIG. 4,the primary antenna element in FIG. 14 includes four dipoles fed by amagic-T feed network 1402. The result of this configuration is anarrower elevation radiation beam that the deflector directs away fromhorizontal direction. The deflector also increases further the isolationwith radial sectors on the opposite side of the WLANAA.

In FIG. 15, a prospective view of an example of another implementationof a WLANAA 1500 utilizing eight (8) radial sectors 1502, 1504, 1506,1508, 1510, 1512, 1514, and 1516 is shown. The WLANAA 1500 includeseight primary antenna elements 1518, 1520, 1522, 1524, 1526, 1528, 1530,and 1532 in signal communication with an array controller 1534. TheWLANAA 1500 also includes absorber elements 1536, 1538, 1540, 1542,1544, 1546, 1548, and 1550 and secondary antenna elements 1552, 1554,and 1556. In this example, the main reflector (not shown) may be acircular conducting cylinder, or ring, that fits concentrically withinthe WLANAA 1500.

In FIG. 16, a top-view 1600 and side-view 1602 of the WLANAA 1604 isshown. As referred to above, in this example the main reflector 1606 maybe a circular conducting cylinder, or ring, that fits concentricallywithin the WLANAA 1604 behind the antenna elements 1608 within theplurality of radial sectors. The antenna elements 1608 may be primaryantenna elements or a combination of primary and secondary antennaelements as described above. The plurality of absorber elements 1610 areshown as located between the antenna elements 1608 of the plurality ofradial sectors. The deflector is also shown as either continuous sheet1612 of conductive material that is parallel to a ceiling or asdiscontinuous deflector elements 1614 that only extend from the mainreflector 1606 and over the antenna elements 1608. Alternatively,instead of being discontinuous, the deflector 1614 may also be a flatcircular ring that extends from the main reflector 1606 and over theantenna elements 1608.

In FIG. 17, a cut-view of an example of an implementation of anindividual primary antenna element 1700 of FIGS. 1, 2, and 3 in anindividual radial sector 1702 of the WLANAA 1704 is shown. The radialsector 1702 includes the main reflector 1706, deflector 1708, and asecondary ground plane 1710. As an example, the main reflector 1706 anddeflector 1708 may be in signal communication via signal path 1712 thatmay be a bonded wire or other ground type connection.

In FIG. 18, a flowchart 1800 showing an example of an implementation ofprocess performed by the WLANAA is shown. The process begins in step1802 and in step 1804 the WLANAA transmits a first plurality oftransmission signals from a plurality of radios located in the radialsectors of a circular housing, wherein the first plurality oftransmission signals are produced with a plurality of primary antennaelements. In step 1806, the WLANAA reflects parts of the first pluralityof transmission signals with a plurality of main reflectors. It isappreciated that the main reflector may include a plurality of mainreflectors elements or, alternatively, may be one continuation mainreflector 1606 as shown in FIG. 16. In step 1808, the WLANAA deflectsparts of the first plurality of transmission signals with a plurality ofdeflectors. Again, it is appreciated that the deflector may include aplurality of main reflectors elements or, alternatively, may be onecontinuation deflector plate 1612 or ring 1614 as shown in FIG. 16. TheWLANAA then absorbs parts of the first plurality of transmission signalswith a plurality of absorber elements in step 1810. The method thenincludes optionally, in step 1812, transmitting a second plurality oftransmission signals from a second plurality of radios located in radialsectors of the circular housing, wherein the second plurality oftransmission signals are produced with a plurality of secondary antennaelements. The process then ends in step 1814.

Moreover, it will be understood that the foregoing description ofnumerous implementations has been presented for purposes of illustrationand description. It is not exhaustive and does not limit the claimedinventions to the precise forms disclosed. Modifications and variationsare possible in light of the above description or may be acquired frompracticing the invention. The claims and their equivalents define thescope of the invention.

What is claimed:
 1. A wireless local area network (“WLAN”) antenna array(“WLANAA”) comprising: a circular housing having a plurality of radialsectors; and a plurality of primary antenna elements and a correspondingplurality of radios, wherein each individual primary antenna element ofthe plurality of primary antenna elements is positioned within anindividual radial sector of the plurality of radial sectors, each radioof the plurality of radios is connected to a corresponding primaryantenna element of the plurality of primary antenna elements, and theplurality of primary antenna elements and corresponding radial sectorsare configured to generate a plurality of radiation patternscorresponding to the plurality of radios and to provide isolationbetween adjacent radial sectors.
 2. The WLANAA of claim 1, furtherincluding a plurality of main reflector elements wherein each mainreflector element of the plurality of main reflector elements is locatedadjacent to each primary antenna element.
 3. The WLANAA of claim 2,wherein the plurality of main reflector elements are part of acontinuous main reflector element that is circular in shape.
 4. TheWLANAA of claim 2, wherein each primary antenna element is located aquarter wavelength away from each main reflector element.
 5. The WLANAAof claim 1, wherein the primary antenna elements are coupled linedipoles.
 6. The WLANAA of claim 5, wherein the coupled line dipoles areconfigured to operate in a band of frequencies described by IEEE802.11a.
 7. The WLANAA of claim 1, wherein the primary antenna elementsare a pair of coupled line dipoles.
 8. The WLANAA of claim 7, whereinthe pair of coupled line dipoles are configured to operate in a band offrequencies described by IEEE 802.11a.
 9. The WLANAA of claim 1, furtherincluding a plurality of secondary antenna elements within the circularhousing, wherein each secondary antenna element of the plurality ofsecondary antenna elements is located within a radial sector of thecircular housing.
 10. The WLANAA of claim 9, wherein each secondaryantenna element is a single bent monopole antenna sharing a radialsector with one of the primary antenna elements.
 11. The WLANAA of claim10, wherein the single bent monopole antennas are configured to operatein a band of frequencies described by IEEE 802.11 b.
 12. The WLANAA ofclaim 10, wherein the single bent monopole antennas are configured tooperate in a band of frequencies described by IEEE 802.11g.
 13. TheWLANAA of claim 9, wherein each secondary antenna element is a twoelement array of bent monopole antennas sharing a radial sector with oneof the primary antenna elements.
 14. The WLANAA of claim 13, wherein thetwo element array is configured to operate in a band of frequenciesdescribed by IEEE 802.11 b.
 15. The WLANAA of claim 13, wherein the twoelement array is configured to operate in a band of frequenciesdescribed by IEEE 802.11g.
 16. The WLANNAA of claim 1 furthercomprising: a plurality of absorber elements wherein each absorberelement of the plurality of the absorber elements is located between anadjacent pair of primary antenna elements.
 17. The WLANAA of claim 16,further including a plurality of deflector elements wherein eachdeflector element of the plurality of deflector elements is locatedadjacent to each primary antenna element.